Imagine the first layoff at Google....

It will happen one day, the Google hiring machine will have moved faster than the revenue stream or shockingly, competition will cause the revenue to reduce below the cost of business and the corner office will have to search for an answer to what so many companies are struggling with today: How should Google dis-employ?

Perhaps they will evolve the 'hiring test process' into the 'exit process'. In a future gmail to all Googlers:

"Due to unforeseen changes in the market, Google has too many people eating free food. We detected this by searching the XBRL of our most recent 10k statement and noticed that the top line tag returns a lower number than the bottom line tag as recorded in the all hands gsheet called http://docs.google.com/cfo-to-employee-quarterly-transparency.

On March 31st, all Google employees are required to take the retainment test at http://google.com/retain-me. Those employees that do not take the test or score in the lowest 13% will be released the next day. Of course as on all days, feel free to take home as much food as you can carry as it reduces our daily garbage footprint and rest assured you will get free search for life.

Sincerely, the Google Board of Directors"

This will be wildly successful and will evolve into an HP style meritocracy process where on a quarterly basis an increasingly harder test will be given. In the second future gmail to all Googlers:

"In order to insure that Googlers are the smartest marketeers on the planet, the board has decided to give the retain-me-nt test every quarter just after earnings are released. The test will be slightly tougher each quarter to insure we are staying ahead of ourselves and the competition. If you score in the lowest 5% you will have to leave the next day, except in those jurisdictions that require longer emancipation processes.

Sincerely, the Google Board of Directors"

This will solve the problem of when to change leadership. Instead of using an old-age limit or a term limit, Google will adopt the following policy:
"A President of Google, or CEO, can retain that position in so long as they are compliant to all Google Policies, written and unwritten, and score above the median ranking of Google employees, thus insuring that leadership is smarter than a majority of the employees."

Inevitably this will lead to a awkward event:

Sergey and Eric walk up to Larry in the cafe, " Uh, Larry we have some bad news..."
"What, is Youtube down ? "
"Well no, it appears that you are in the 49th percentile"
"whoa...I knew...someday, but I was just about to press the button the beta of my latest '20% time' product idea "
Eric perks up " What is it? "
"Interesting timing come to think of it, the concept is a Youtube-mashup-reality-show of our quarterly retainment test. People watch as our employees compete to finish the test live on Youtube. At the end of the show the lowest 5% are are forced to leave. Viewers get endeared to the employees, show after show, as they get closer to the line, while employers start bidding to hire the employees who have to leave. At the same time there would be employment ads running on the bottom and right. Its going to be http://island.google.com"
Sergey mulls this over, then exclaims "Brilliant, I just got an idea, if you accept a demotion from president to vice president then your 49th percentile is sufficient to stay on the island"
Eric chips in " Yea, then we can track your scores and have a big ratings hit as you fall below 5%. This could be huge. We could get Carly to host the show, she would be perfect."

"Yes, then the next night we can host 'Who wants to be a Googlenaire?' Where candidates across the globe, all visualized in google earth of course, compete to take the test to fill the vacated slots. It's perfect, we advertise our employment issues and make money from the transparency!... We might have to give the test weekly!"

Many years later " Live, tonight Larry is leaving us after many tests, but in the wings is one of our youngest players ever. Cindy Lu, who at the age of 9, is only 2 questions away from taking Larry's place at the Googleplex, of course all child labor laws will be followed in case she wins. I'm Carly and this is Google-tainment Tonight!......."